The present invention relates generally to oil seals and more particularly, to a combination seal and oil directing device.
Still further, the invention relates to a device that enables oil, including relatively heavy oil, to be picked up from a sump and delivered to a pump which operates only intermittently, and serves to supply pressure to an annular piston. The piston, in turn, when energized, acts through a multi-plate clutch and tends to lock the spider gears of a differential against relative rotation and thus lock the drive axles of a vehicle together. When there is little or no relative motion between the axles, the pump ceases to function transiently and the axles are unlocked. The seal also functions to deliver oil sufficient to permit somewhat limited slippage of the two axles.
The invention preferably includes a large stamping, a small circular stamping, and a third auxiliary stamping that serves, in cooperation with the main stamping, to form a dip tube to deliver the oil from the sump to the oil pump, where it performs to above-described functions. In a preferred form, the main stamping includes one or more tabs to prevent rotation relative to the ring gear with which it is associated in use. Normally, the ring gear rotates and the seal directing device does not. Herein, although the plenum seal of the invention has the oil directing and other functions, it is sometimes referred to herein for convenience merely as a "seal".
According to the invention, a preferred form of the device includes a part facing the intake of the oil pump, with a seal band extending around the exterior thereof, and an opening of a smaller diameter nearer the center thereof, which also features a seal extending in the opposite direction. On the side opposite the oil outlet, are preferably several tabs that serve to locate the seal in its environment.
One of the components of the seal includes a cover element preferably having associated therewith a cover with an offset area serving to define, in combination with the main body unit, an oil passage. This cover is held to the main body unit by a series of tabs and preferably, also by adhesive surrounding the formation but leaving the oil inlet free. The differential housing includes a sump, and hence the oil seal has an opening at the bottom, an area of thin, and preferably enlarging, dimension leading to the oil outlet opening in the seal, and terminating at the opening.
The differential housing contains a pinion or driving gear, which serve to rotate a ring gear and its associated components, at a reduced speed relative to the pinion gear.
Referring again to the side with the opening, this side faces the opening in the ring gear for the inlet of an oil pump. The pump consists of two gears or rotors which rotate at different speeds relative to each other within a housing. Preferably, the pieces are of a "Gerotor" design that takes oil in through openings inside a cover plate that lies partially within the ring gear and forces oil out in the opposite axial direction against a bonded piston to actuate a multi-plate clutch.
The gear pump includes an exterior housing, an internal rotor and an external rotor. The internal rotor includes teeth on its inner diameter for engaging one axle and has outwardly directed formations thereon, and the external gear has internal formations thereon. These two, collectively, form an oil pump which has an inlet on one axial side and an outlet on the opposite axial side, with the inlet and outlet being spaced apart by about half a diameter. The oil is then pumped into a cavity in a housing containing a bonded piston. Upon sensing oil pressure, the piston moves so as to compress the discs of a multi-plate clutch and ultimately causes the drive axles to rotate together.
One drive axle extends through an opening in the ring gear, and this drive axle is splined so as to fit into the internal gear of the Gerotor, the driven clutch plates, and one of the side gears of the spider set. The second axle is internally splined to the other side gear. When the oil acts on the bonded piston, it tends to lock the internal splines on the first shaft to the second shaft, by locking out the spider carrier, thus causing both shafts to rotate as a unit, and doing away with differential action. When the bonded piston sees less oil pressure, it releases its grip, allowing the clutch plates to release to a greater or less degree, and the differential is then free to provide more or less differential action.
Accordingly, it is an object of the present invention to provide a plenum seal having certain advantages and characteristics.
Another object of the invention is to provide a plenum seal that seals on two diameters, that includes an oil passage therethrough, extending from outside both diameters to a point intermediate the two diameters.
Yet another object of the invention is to provide an oil seal that is made from inexpensive, preferably, stamped parts.
Still another object of the invention is to provide a seal having three components, one of which comprises a cover for a part of the other.
A further object of the invention is to provide a plenum seal having a flat plate with an O.D. seal, an opening in the flat plate, a stamping with an I.D. seal, and a cover, preferably of a contoured design, that fits over the flat plate to provide an oil supply line or area to a given part of an associated pump mechanism.
A still further object is to provide an oil seal that includes tabs for preventing rotation and thus insuring that the seal will remain in place relative to a rotating ring gear assembly.
Another object of the invention is to provide an oil seal of a design which may be generally followed in practice in a number of different sizes and which will serve to fulfill the requirements for an effective oil seal for a locking differential.
Yet another object of the invention is to provide an oil seal that includes a spring loaded lip on the inside sealing surface, and a non-spring loaded lip on the outside sealing surface, with the two lips facing in opposite axial directions.
Another object of the invention is to provide an oil seal assembly having oppositely directed seals, an oil delivery tube, and an oil outlet, with the delivery tube lying on the side opposite the outer diameter seal.
A further object of the invention is to provide a seal assembly with an oil pickup on one side of an outer diameter seal and an oil discharge opening on the other side.
A still further object of the invention is to provide a seal assembly that can maintain a volume of oil in the space between two seals for supplying the needs of an oil pump from time to time.
The invention achieves its objects, and other inherent objects and advantages by providing a plenum seal for a differential ring gear assembly, said seal including a portion sealing on an inside diameter of a part associated in use with the ring gear, such as an oil pump housing, and a portion sealing on an enlarged diameter of such part to create a sealed region between them, an oil outlet in the inter-seal area, and an oil inlet lying outside the sealed area, whereby oil may be picked up and pumped from a sump into a specially constructed differential, wherein it will serve, under proper conditions, to lock the drive axles together and enable a substantial torque to be applied to both axles.
The manner in which the foregoing and other objects are achieved in practice will become more clearly apparent when reference is made to the following detailed description of the present invention and to the accompanying drawings, in which like numbers indicate corresponding parts throughout.